diff --git a/qdlt/dlt_protocol.h b/qdlt/dlt_protocol.h
index 729eb7aa..3b0dcfb3 100644
--- a/qdlt/dlt_protocol.h
+++ b/qdlt/dlt_protocol.h
@@ -164,7 +164,10 @@
 #define DLT_SCOD_HEX        0x00010000
 #define DLT_SCOD_BIN        0x00018000
 /*
- * Definitions of DLT services.
+ * Definitions of DLT service IDs.
+ *
+ * Should correspond to AUTOSAR DLT protocol specification the DLT service
+ * implementation conforms to.
  */
 #define DLT_SERVICE_ID_SET_LOG_LEVEL                   0x01 /**< Service ID: Set log level */
 #define DLT_SERVICE_ID_SET_TRACE_STATUS                0x02 /**< Service ID: Set trace status */
diff --git a/qdlt/dltmessagematcher.h b/qdlt/dltmessagematcher.h
index 88cf41b8..318577b2 100644
--- a/qdlt/dltmessagematcher.h
+++ b/qdlt/dltmessagematcher.h
@@ -11,6 +11,17 @@
 
 class QDltMsg;
 
+/**
+ * A class which can be used to set search parameters for matching on potential DLT messages.
+ *
+ * Offers functions to search different parts of a DLT message.
+ * Offers the option to search either the header, the payload, or both.
+ * Searches can be case-sensitive - default is case-insensitive.
+ * The pattern to search a payload can be either a regular expression or plain text.
+ *
+ * Currently used by the UI search dialog.
+ * @see SearchDialog
+ */
 class QDLT_EXPORT DltMessageMatcher
 {
 public:
@@ -46,9 +57,32 @@ class QDLT_EXPORT DltMessageMatcher
         m_messageIdFormat = msgIdFormat;
     }
 
+    /**
+     *
+     * @return `true` if `msg` matches all of:
+     *  - application ID set in `this`
+     *  - context ID set in `this`
+     *  - timestamp range set in `this`
+     *  - pattern matches either the `msg` header or payload
+     *  `false` otherwise.
+     *
+     *  @see SearchDialog::findMessages
+     */
     bool match(const QDltMsg& message, const Pattern& pattern) const;
+
 private:
+
+    /**
+     * Match the application ID in `appId` against `this`
+     *
+     * @return `true` if `this` has no application ID set or the IDs match exactly, false otherwise
+     */
     bool matchAppId(const QString& appId) const;
+    /**
+     * Match the context ID in `ctxId` against `this`
+     *
+     * @return `true` if `this` has no application ID set or the IDs match exactly, false otherwise
+     */
     bool matchCtxId(const QString& ctxId) const;
     bool matchTimestampRange(unsigned int ts) const;
 private:
diff --git a/qdlt/fieldnames.h b/qdlt/fieldnames.h
index 447d2434..80acd5e0 100644
--- a/qdlt/fieldnames.h
+++ b/qdlt/fieldnames.h
@@ -6,6 +6,12 @@
 #include <QObject>
 #include <QString>
 
+/**
+ * Class to obtain human-readable names for DLT message parts,
+ * and UI element properties.
+ *
+ * @see MainWindow::initView
+ */
 class QDLT_EXPORT FieldNames : public QObject
 {
     Q_OBJECT
@@ -42,9 +48,9 @@ class QDLT_EXPORT FieldNames : public QObject
     static bool getColumnShown(Fields cn,QDltSettingsManager *settings = NULL);
 
 signals:
-    
+
 public slots:
-    
+
 };
 
 #endif // FIELDNAMES_H
diff --git a/qdlt/qdltargument.h b/qdlt/qdltargument.h
index 04c53ea1..581c49ff 100644
--- a/qdlt/qdltargument.h
+++ b/qdlt/qdltargument.h
@@ -31,7 +31,8 @@
 //! One argument of a DLT message.
 /*!
   This class contains one argument of a DLT message.
-  A QDltMessage contains several Arguments.
+  A QDltMessage contains several QDltArgument, like a DLT message contains
+  multiple arguments.
 */
 class QDLT_EXPORT QDltArgument
 {
diff --git a/qdlt/qdltbase.h b/qdlt/qdltbase.h
index bccc7496..219ee969 100644
--- a/qdlt/qdltbase.h
+++ b/qdlt/qdltbase.h
@@ -28,10 +28,11 @@
 
 constexpr const auto DLT_MAX_MESSAGE_LEN = 1024*64;
 
-//! Base class for all DLT classes.
-/*!
-  This class contains helper functions needed for all DLT operations and classes.
-*/
+/**
+ * Base class for all DLT classes.
+ *
+ * This class contains helper functions needed for all DLT operations and classes.
+ */
 class QDLT_EXPORT QDlt
 {
 public:
diff --git a/qdlt/qdltconnection.h b/qdlt/qdltconnection.h
index 656f29c3..fe5e4c78 100644
--- a/qdlt/qdltconnection.h
+++ b/qdlt/qdltconnection.h
@@ -82,6 +82,11 @@ class QDLT_EXPORT QDltDataView
     int m_position;
 };
 
+/**
+ * Base class for classes representing a connection for user commands & UI.
+ *
+ * Has concrete methods.
+ */
 class QDLT_EXPORT QDltConnection
 {
 
@@ -102,6 +107,11 @@ class QDLT_EXPORT QDltConnection
     bool parseAscii(QDltMsg &msg);
 
     void clear();
+    /**
+     * Add data to a connection, to be parsed.
+     *
+     * @see MainWindow::read
+     */
     void add(const QByteArray &bytes);
 
     QByteArray data;
diff --git a/qdlt/qdltcontrol.h b/qdlt/qdltcontrol.h
index 4c1abac6..6455f1ef 100644
--- a/qdlt/qdltcontrol.h
+++ b/qdlt/qdltcontrol.h
@@ -32,6 +32,17 @@
 
 #include "export_rules.h"
 
+/**
+ * This class contains various signals used in MainWindow, corresponding to user commands.
+ * Execution of the commands is in UI code. Signals defined here are
+ * connected to slots in e.g. MainWindow.
+ * (rem. private slots can be invoked by arbitrary components)
+ *
+ * Also passed to plugins via MainWindow -> QDltPluginManager
+ *
+ * @see MainWindow::sendInjection
+ * @see MainWindow::jumpToMsgSignal
+ */
 class QDLT_EXPORT QDltControl : public QObject
 {
       Q_OBJECT
diff --git a/qdlt/qdltctrlmsg.h b/qdlt/qdltctrlmsg.h
index acda8b41..252de83c 100644
--- a/qdlt/qdltctrlmsg.h
+++ b/qdlt/qdltctrlmsg.h
@@ -12,6 +12,16 @@
 
 namespace qdlt::msg::payload {
 
+/**
+ * Most DLT service IDs referenced here can be found in the AUTOSAR DLT specification.
+ *
+ * Note the AUTOSAR spec does not reserve IDs.
+ */
+
+/**
+ * A struct associated with the `GetLogInfo` DLT service command,
+ * to retrieve log levels for all registered contexts.
+ */
 struct GetLogInfo {
     struct App {
         struct Ctx {
@@ -30,15 +40,27 @@ struct GetLogInfo {
     std::vector<App> apps;
 };
 
+/**
+ * A struct associated with the `GetSoftwareVersion` DLT service command,
+ * to retrieve a string denoting the system's software version.
+ */
 struct GetSoftwareVersion {
 };
 
+/**
+ * A struct associated with the `GetDefaultLogLevel` DLT service command,
+ * to retrieve the currently set default log level.
+ */
 struct GetDefaultLogLevel
 {
     uint8_t logLevel;
     uint8_t status;
 };
 
+/**
+ * A struct associated with the `GetDefaultLogLevel` DLT service command,
+ * to set a log level.
+ */
 struct SetLogLevel {
     uint8_t status;
 };
diff --git a/qdlt/qdltdefaultfilter.h b/qdlt/qdltdefaultfilter.h
index b1adf642..4d3bbdf8 100644
--- a/qdlt/qdltdefaultfilter.h
+++ b/qdlt/qdltdefaultfilter.h
@@ -36,6 +36,12 @@
 #include "qdltfilterlist.h"
 
 
+/**
+ * "Default" filters loaded by MainWindow - initialises the indexer.
+ * this ∋ `QDltFilterList` ∋ `QDltFilter`
+ *
+ * @see MainWindow
+ */
 class QDLT_EXPORT QDltDefaultFilter
 {
 public:
diff --git a/qdlt/qdltexporter.h b/qdlt/qdltexporter.h
index a4652cea..e84d9bcb 100644
--- a/qdlt/qdltexporter.h
+++ b/qdlt/qdltexporter.h
@@ -15,6 +15,13 @@
 #define QDLT_DEFAULT_EXPORT_SIGNATURE "ITSOEACNYUMRP"
 #define QDLT_DEFAULT_EXPORT_DELIMITER ','
 
+/**
+ * Class used for UI export functions. Currently implemented as a thread that must be fed
+ * messages to export.
+ *
+ * There is no interface toward a collection of DLT messages, but instead
+ * functions are referencing single QDltMsg instances. This is suboptimal.
+ */
 class QDLT_EXPORT QDltExporter : public QThread
 {
     Q_OBJECT
diff --git a/qdlt/qdltfile.h b/qdlt/qdltfile.h
index 1b508645..600af53c 100644
--- a/qdlt/qdltfile.h
+++ b/qdlt/qdltfile.h
@@ -35,6 +35,9 @@
 #include <time.h>
 #include <QCache>
 
+/**
+ * Object containing a single QFile and an index to offsets of DLT messages in it.
+ */
 class QDLT_EXPORT QDltFileItem
 {
 public:
@@ -49,11 +52,12 @@ class QDLT_EXPORT QDltFileItem
 
 };
 
-//! Access to a DLT log file.
-/*!
-  This class provide access to DLT log file.
-  This class is currently not thread safe.
-*/
+/**
+ * Access to a DLT log file.
+ *
+ * This class provide access to DLT log file.
+ * This class is currently not thread safe.
+ */
 class QDLT_EXPORT QDltFile : public QDlt
 {
 public:
diff --git a/qdlt/qdltfilter.h b/qdlt/qdltfilter.h
index ccf4f11b..770442fd 100644
--- a/qdlt/qdltfilter.h
+++ b/qdlt/qdltfilter.h
@@ -36,6 +36,9 @@
 #include "qdltmsg.h"
 
 
+/**
+ * Represents a filter set in the UI.
+ */
 class QDLT_EXPORT QDltFilter
 {
 public:
diff --git a/qdlt/qdltfilterindex.h b/qdlt/qdltfilterindex.h
index 62eeb237..54329639 100644
--- a/qdlt/qdltfilterindex.h
+++ b/qdlt/qdltfilterindex.h
@@ -32,6 +32,11 @@
 #include "export_rules.h"
 #include "qdltfilterlist.h"
 
+/**
+ * Maybe supposed to represent a file with filters applied to it. Unclear usage of index.
+ *
+ * Missing getters / interface.
+ */
 class QDLT_EXPORT QDltFilterIndex
 {
 public:
diff --git a/qdlt/qdltfilterlist.h b/qdlt/qdltfilterlist.h
index 62da6cc6..8ad6c832 100644
--- a/qdlt/qdltfilterlist.h
+++ b/qdlt/qdltfilterlist.h
@@ -35,7 +35,9 @@
 #include <QXmlStreamReader>
 #include <QXmlStreamWriter>
 
-
+/**
+ * A list of filters applied in the UI
+ */
 class QDLT_EXPORT QDltFilterList
 {
 public:
diff --git a/qdlt/qdltimporter.h b/qdlt/qdltimporter.h
index c9e92fea..bdff0256 100644
--- a/qdlt/qdltimporter.h
+++ b/qdlt/qdltimporter.h
@@ -156,6 +156,12 @@ typedef struct mdf_hdr {
         quint64 link_count;     /* number of links in link section */
 } PACKED mdf_hdr_t;
 
+/**
+ * Class used for UI import functions. Currently implemented as a thread that must be fed
+ * messages individually - this is suboptimal.
+ *
+ * Function names are nondescript.
+ */
 class QDLT_EXPORT QDltImporter : public QThread
 {
     Q_OBJECT
diff --git a/qdlt/qdltipconnection.h b/qdlt/qdltipconnection.h
index 19095ad4..d0478f98 100644
--- a/qdlt/qdltipconnection.h
+++ b/qdlt/qdltipconnection.h
@@ -32,6 +32,15 @@
 #include "export_rules.h"
 #include "qdltconnection.h"
 
+/**
+ * A (conceptual) connection toward a DLT service.
+ *
+ * Currently set up as an inheritance scheme - QDltConnection has concrete functions
+ * for parsing.
+ * This class keeps track of the remote host(name). Also port, although IP has no port info.
+ *
+ * Used by the UI (main window).
+ */
 class QDLT_EXPORT QDltIPConnection : public QDltConnection
 {
 public:
diff --git a/qdlt/qdltmessagedecoder.h b/qdlt/qdltmessagedecoder.h
index 3e073a7a..a0aa3bb9 100644
--- a/qdlt/qdltmessagedecoder.h
+++ b/qdlt/qdltmessagedecoder.h
@@ -27,6 +27,12 @@
 
 class QDltMsg;
 
+/**
+ * An interface for modifying a QDltMsg based on plugin-specific functionality.
+ *
+ * Designing the decoding to be done by expecting a message to be its own object
+ * is suboptimal and does not allow efficient organisation (memory, temporal, or otherwise).
+ */
 class QDLT_EXPORT QDltMessageDecoder
 {
 public:
diff --git a/qdlt/qdltmsg.cpp b/qdlt/qdltmsg.cpp
index 5b8b23b3..b6bf7794 100644
--- a/qdlt/qdltmsg.cpp
+++ b/qdlt/qdltmsg.cpp
@@ -309,6 +309,15 @@ quint32 QDltMsg::checkMsgSize(const char *data,quint32 size,bool supportDLTv2)
     }
 }
 
+/**
+ * Attempt to parse a valid DLT message from `buf`, with an optional storage header.
+ *
+ * It will attempt to parse DLTv1 only if `supportDLTv2` is `false`.
+ *
+ * @return `false` if there is not enough data in `buf` for a valid message header or
+ * the entire message as indicated in the header's length field. Also `false` if
+ * arguments could not be parsed correctly. Otherwise, `true`.
+ */
 bool QDltMsg::setMsg(const QByteArray& buf, bool withStorageHeader,bool supportDLTv2)
 {
     unsigned int offset;
@@ -926,6 +935,14 @@ bool QDltMsg::parseArguments()
     return true;
 }
 
+/**
+ * Attempt to create a valid DLT messages in `buf`, optionally
+ * preceded by a storage header, from the state of `this` object.
+ *
+ * Modifies `this.payload` to contain the message's arguments.
+ *
+ * @return `false` if calling `QDltArgument::getArgument` fails, `true` otherwise
+ */
 bool QDltMsg::getMsg(QByteArray &buf,bool withStorageHeader) {
     DltStorageHeader storageheader;
     DltStandardHeader standardheader;
@@ -1073,6 +1090,12 @@ int QDltMsg::sizeArguments() const
     return arguments.size();
 }
 
+/**
+ * Set `argument` to the argument of this message at `index`.
+ *
+ * @return `false` if `index` is outside the range of currently contained arguments, `true`
+ * otherwise.
+ */
 bool QDltMsg::getArgument(int index,QDltArgument &argument) const
 {
       if(index<0 || index>=arguments.size())
diff --git a/qdlt/qdltmsg.h b/qdlt/qdltmsg.h
index aebd9e60..6b7018c1 100644
--- a/qdlt/qdltmsg.h
+++ b/qdlt/qdltmsg.h
@@ -28,18 +28,18 @@
 #include "qdltbase.h"
 #include "qdltargument.h"
 
-//! Access to a DLT message.
-/*!
-  This class provide access to a single DLT message from a DLT log file.
-  This class is currently not thread safe.
-*/
+/**
+ * An object modelling a DLT message.
+ * Can be used to create custom messages and to parse valid DLT messages (e.g. from a file).
+ *
+ * @warning No functions in this class are thread-safe.
+ */
 class QDLT_EXPORT QDltMsg
 {
 public:
-    //! Constructor.
-    /*!
-      This call clears all variables of the argument.
-    */
+    /**
+     * Constructor. Clears all variables of the argument.
+     */
     QDltMsg();
 
     //! The type of the DLT message.
diff --git a/qdlt/qdltoptmanager.h b/qdlt/qdltoptmanager.h
index 8ce3cd57..6175c847 100644
--- a/qdlt/qdltoptmanager.h
+++ b/qdlt/qdltoptmanager.h
@@ -41,6 +41,9 @@ enum class e_inputmode
     SERIAL = 2,
 };
 
+/**
+ * Holder for & parser of application options (from command-line / argv).
+ */
 class QDLT_EXPORT QDltOptManager
 {
 public:
diff --git a/qdlt/qdltplugin.h b/qdlt/qdltplugin.h
index 5bb4688a..8d6b65c6 100644
--- a/qdlt/qdltplugin.h
+++ b/qdlt/qdltplugin.h
@@ -8,10 +8,10 @@
 #include "export_rules.h"
 
 
-//! Access class to a DLT Plugin to decode, view and control DLT messages
-/*!
-  This class loads a DLT Viewer Plugin library and provides functions to access the plugin.
-*/
+/**
+ * Class representing a DLT plugin. Plugins can be used to decode, view and control DLT messages.
+ * This class loads a DLT Viewer Plugin library and provides functions to access the plugin.
+ */
 class QDLT_EXPORT QDltPlugin
 {
 public:
diff --git a/qdlt/qdltsegmentedmsg.h b/qdlt/qdltsegmentedmsg.h
index 8c03daf5..58a6b74b 100644
--- a/qdlt/qdltsegmentedmsg.h
+++ b/qdlt/qdltsegmentedmsg.h
@@ -26,10 +26,14 @@
 
 #include <qdltmsg.h>
 
-//! Combine segmented network messages
-/*!
-  This class combines several segmented network message to a single message
-*/
+/**
+ * Combine segmented network messages
+ * This class combines several segmented network message to a single message.
+ * Must first add those messages using the `add()` function.
+ *
+ * this -> DltSegmentationPlugin::decodeMsg -> QDltMsg
+ *
+ */
 class QDLT_EXPORT QDltSegmentedMsg
 {
 public:
diff --git a/qdlt/qdltserialconnection.h b/qdlt/qdltserialconnection.h
index fcd918ff..c4932b9b 100644
--- a/qdlt/qdltserialconnection.h
+++ b/qdlt/qdltserialconnection.h
@@ -35,6 +35,16 @@
 
 class QSerialPort;
 
+/**
+ * Represents a serial connection for the purposes of the UI.
+ *
+ * Currently set up as an inheritance scheme - QDltConnection has concrete functions
+ * for parsing.
+ *
+ * @see QDltIPConnection
+ * @see QDltTCPConnection
+ * @see QDltUDPConnection
+ */
 class QDLT_EXPORT QDltSerialConnection : public QDltConnection
 {
 public:
diff --git a/qdlt/qdltsettingsmanager.h b/qdlt/qdltsettingsmanager.h
index 7cc64fca..1a2d2fc4 100644
--- a/qdlt/qdltsettingsmanager.h
+++ b/qdlt/qdltsettingsmanager.h
@@ -30,6 +30,12 @@
 
 #define DEFAULT_REFRESH_RATE 20
 
+/**
+ * Application options. Used by the UI.
+ *
+ * @see MainWindow
+ * @see SettingsDialog
+ */
 class QDLT_EXPORT QDltSettingsManager
 {
 // Singleton pattern
diff --git a/qdlt/qdlttcpconnection.h b/qdlt/qdlttcpconnection.h
index f650bf8d..c11c8687 100644
--- a/qdlt/qdlttcpconnection.h
+++ b/qdlt/qdlttcpconnection.h
@@ -34,6 +34,16 @@
 
 class QTcpSocket;
 
+/**
+ * Represents a TCP connection for the purposes of the UI.
+ *
+ * Currently set up as an inheritance scheme - QDltConnection has concrete functions
+ * for parsing.
+ *
+ * @see QDltIPConnection
+ * @see QDltSerialConnection
+ * @see QDltUDPConnection
+ */
 class QDLT_EXPORT QDltTCPConnection : public QDltIPConnection
 {
 public:
diff --git a/qdlt/qdltudpconnection.h b/qdlt/qdltudpconnection.h
index 208eee19..10f6c8bb 100644
--- a/qdlt/qdltudpconnection.h
+++ b/qdlt/qdltudpconnection.h
@@ -34,6 +34,16 @@
 
 class QUdpSocket;
 
+/**
+ * Represents receiving messages from a UDP remote endpoint for the purposes of the UI.
+ *
+ * Currently set up as an inheritance scheme - QDltConnection has concrete functions
+ * for parsing.
+ *
+ * @see QDltIPConnection
+ * @see QDltSerialConnection
+ * @see QDltTCPConnection
+ */
 class QDLT_EXPORT QDltUDPConnection : public QDltIPConnection
 {
 public:
diff --git a/src/searchdialog.cpp b/src/searchdialog.cpp
index 1d0da1b0..504798ee 100644
--- a/src/searchdialog.cpp
+++ b/src/searchdialog.cpp
@@ -192,6 +192,14 @@ void SearchDialog::focusRow(long int searchLine)
     model->modelChanged();
 }
 
+/**
+ * Called from findNextClicked and findPreviousClicked
+ *
+ * @return 2 if an invalid context or application ID is set for search,
+ * 1 if a match of the search text is found or an invalid regular expression is given in search
+ *   text,
+ * 0 otherwise.
+ */
 int SearchDialog::find()
 {
     isSearchCancelled = false;
@@ -337,6 +345,9 @@ int SearchDialog::find()
      fIs_APID_CTID_requested = false;
     }
 
+    /* Actual search taking place here,
+     * will set this->match accordingly.
+     */
     findMessages(startLine,searchBorder,searchTextRegExpression);
 
     emit searchProgressChanged(false);
@@ -437,6 +448,10 @@ void SearchDialog::findMessages(long int searchLine, long int searchBorder, QReg
             pluginManager->decodeMsg(msg, fSilentMode);
         }
 
+        /*
+         * Search for a match
+         * Note the message `msg` is decoded here (see above)
+         */
         const bool matchFound = getRegExp() ? matcher.match(msg, searchTextRegExp) : matcher.match(msg, getText());
         if (!matchFound)
         {